You can either use MySQL or SQLite. SQLite is easier to set up.
If you use Ubuntu you can use the PPA by executing add-apt-repository ppa:jklmnn/groundapps
.
To install the backend manually , go to http://your.path/.
Fill up the form, click on create!
That's all.
Please do never hesitate to open an issue!
I know there a some bugs, most likely because I had no idea how to do it otherwise and therefore had to use a workaround.